Agricultural baler with auxiliary power system

ABSTRACT

An agricultural baler includes a chassis, a flywheel carried by the chassis, and a driveline associated with the flywheel and couplable with a power take-off (PTO) of a traction unit. The agricultural baler further includes an auxiliary power system coupled with the driveline. The auxiliary power system is configured for receiving power from the driveline, storing the power, and transmitting the stored power back to the driveline.

CROSS REFERENCE TO RELATED APPLICATION

This application is the National Stage of International Application No.PCT/EP2015/065467 filed Jul. 7, 2015, which claims priority to BelgiumPatent Application No. 2014/0538 filed Jul. 9, 2014, the contents ofwhich are incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to agricultural balers, and, moreparticularly, to systems for powering such balers.

DESCRIPTION OF THE RELATED ART

Agricultural harvesting machines, such as balers, are used toconsolidate and package crop material so as to facilitate the storageand handling of the crop material for later use. In the case of hay, amower-conditioner is typically used to cut and condition the cropmaterial for windrow drying in the sun. In the case of straw, anagricultural combine discharges non-grain crop material from the rear ofthe combine defining the straw (such as wheat or oat straw) which is tobe picked up by the baler. The cut crop material is typically raked anddried, and a baler, such as a large square baler or round baler,straddles the windrows and travels along the windrows to pick up thecrop material and form it into bales.

On a large square baler, a pickup unit at the front of the baler gathersthe cut and windrowed crop material from the ground. The pickup unitincludes a pickup roll, and optionally may include other components suchas side shields, stub augers, wind guard, etc.

A packer unit is used to move the crop material from the pickup unit toa duct or pre-compression chamber. The packer unit forms a wad of cropwithin the pre-compression chamber which is then transferred to a mainbale chamber. (For purposes of discussion, the charge of crop materialwithin the pre-compression chamber will be termed a “wad”, and thecharge of crop material after being compressed within the main balechamber will be termed a “flake”). Typically such a packer unit includespacker tines or forks to move the crop material from the pickup unitinto the pre-compression chamber. Instead of a packer unit it is alsoknown to use a rotor cutter unit which chops the crop material intosmaller pieces.

A stuffer unit transfers the wad of crop material in charges from thepre-compression chamber to the main bale chamber. Typically such astuffer unit includes stuffer forks which are used to move the wad ofcrop material from the pre-compression chamber to the main bale chamber,in sequence with the reciprocating action of a plunger within the mainbale chamber.

In the main bale chamber, the plunger compresses the wad of cropmaterial into flakes to form a bale and, at the same time, graduallyadvances the bale toward the outlet of the bale chamber. The plungerreciprocates, back and forth, toward and away from the discharge end ofthe baler. The plunger may include a number of rollers which extendlaterally outward from the sides of the plunger. The rollers on eachside of the plunger are received within a respective plunger slot formedin the side walls of the bale chamber, with the plunger slots guidingthe plunger during the reciprocating movements.

When enough flakes have been added and the bale reaches a full (or otherpredetermined) size, a number of knotters are actuated which wrap andtie twine, cord or the like around the bale while it is still in themain bale chamber. The twine is cut and the formed baled is ejected outthe back of the baler as a new bale is formed.

During a compression cycle of the plunger as described above, theplunger moves through a compression stroke as it advances into the mainbale chamber, with the highest load on the plunger occurring at the endof each compression stroke. As balers become increasingly larger, thepeak loads on the plunger during compression strokes likewise becomeincreasingly larger. One way to compensate for these higher peak loadsis to use a larger flywheel coupled with a gearbox which drives theplunger. As the plunger reaches the end of the compression stroke, themomentum of the heavier flywheel helps carry the plunger through thepeak load at the end of the compression stroke. If the flywheel is notheavy enough then high loads are transferred back through the drivelineto the base unit, which can result in lugging down of the engine onboardthe base unit. However, a flywheel which is too large is alsoundesirable since it typically requires a base unit with a largerhorsepower (HP) rating to start and drive the flywheel forming part ofthe driveline of the baler.

US 2010/0108413 describes a baler having a jog drive system drivinglyconnected within the primary drive system. This jog drive system servesas a source of power to the various performance systems in the balerwhen movement of components within the baler is required for maintenanceor adjustment. The jog drive system comprises a jog motor which can bein the form of a hydraulic motor, an electric motor or other suitabledrive mechanism for slowly rotating the flywheel of the baler andthereby advancing all performance systems. The jog motor can beconnected to a hydraulic system of the tractor, to an electric system ofthe tractor or can be provided with other sources of power input. Thisjog drive system is foreseen to assist the operator when maintenance oradjustment is needed to the baler, and does not have an impact on theoperation of the plunger, since the jog drive system is only able toslowly rotate the flywheel.

In EP 1 974 601, a similar auxiliary drive is foreseen which functionsas a starting arrangement acting on the main drive of the baler andwhich is capable of acting as a sole drive of the baler or as a driveassisting the main drive in the first phase of the process of startingthe baler. During the starting process, the main drive will accelerateto a higher speed than the auxiliary drive by means of a freewheelarrangement, whereupon the auxiliary drive ceases to have any effect onthe remainder of the starting process. This auxiliary drive is used toovercome the problem that sometimes it is difficult to start up thebaler and will assist only during this start-up phase, after which itceases to have any effect.

What is needed in the art is an agricultural baler which accommodateslarge peak loads during compression strokes of the plunger.

SUMMARY OF THE INVENTION

The present invention provides an agricultural baler with an auxiliarypower system (APS) which scavenges power from the driveline of the balerduring off-peak load periods and transmits power back to the drivelinefor use during peak load periods.

The invention in one form is directed to an agricultural baler,including a chassis, a flywheel carried by the chassis, and a drivelineassociated with the flywheel and couplable with a power take-off (PTO)of a traction unit. The agricultural baler is characterized by anauxiliary power system coupled with the driveline. The APS is configuredfor receiving power from the driveline, storing the power, andtransmitting the stored power back to the driveline.

An advantage of the present invention is that power is scavenged fromthe baler during off-peak load periods, and transmitted back to thedriveline for use during peak loads.

Another advantage is that a base unit with a smaller HP rating can beused to drive the baler.

Yet another advantage is that the baler can be equipped with a smallerflywheel.

A further advantage is that lower PTO power is required: up to 40%,depending on the duty cycle of the baler.

A still further advantage is that fuel consumption is reduced, since asmaller traction unit may be used.

Another advantage is that the APS results in greater comfort for theoperator, since peak impulse loads are not transferred back through thedriveline to the traction unit.

BRIEF DESCRIPTION OF THE DRAWINGS

The above-mentioned and other features and advantages of this invention,and the manner of attaining them, will become more apparent and theinvention will be better understood by reference to the followingdescription of embodiments of the invention taken in conjunction withthe accompanying drawings, wherein:

FIG. 1 is a perspective cutaway view showing the internal workings of alarge square baler, which may include an APS of the present invention;

FIG. 2 is a perspective view of the driveline, gearbox and APS shown inFIG. 1;

FIG. 3 is a block diagram showing a simplified embodiment of the APS ofthe present invention;

FIG. 4 is a control schematic of an embodiment of the APS of the presentinvention; and

FIG. 5 is a graphical illustration of required power during compressioncycles of the baler, hydraulic power input by the APS, and resultant PTOpower as a result of the power input by the APS.

Corresponding reference characters indicate corresponding partsthroughout the several views. The exemplifications set out hereinillustrate embodiments of the invention, and such exemplifications arenot to be construed as limiting the scope of the invention in anymanner.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to the drawings, and more particularly to FIG. 1, there isshown a perspective cutaway view showing the internal workings of alarge square baler 10. Baler 10 operates on a two stage feeding system.Crop material is lifted from windrows into the baler 10 using a pickupunit 12. The pickup unit 12 includes a rotating pickup roll 14 withtines 16 which move the crop rearward toward a packer unit 18. Anoptional pair of stub augers (one of which is shown, but not numbered)are positioned above the pickup roll 14 to move the crop materiallaterally inward. The packer unit 18 includes packer tines 20 which pushthe crop into a pre-compression chamber 22 to form a wad of cropmaterial. The packer tines 20 intertwine the crop together and pack thecrop within the pre-compression chamber 22. Pre-compression chamber 22and packer tines 20 function as the first stage for crop compression.Once the pressure in the pre-compression chamber 22 reaches apredetermined sensed value, a stuffer unit 24 moves the wad of crop fromthe pre-compression chamber 22 to a main bale chamber 26. The stufferunit 24 includes stuffer forks 28 which thrust the wad of crop directlyin front of a plunger 30, which reciprocates within the main balechamber 26 and compresses the wad of crop into a flake. Stuffer forks 28return to their original stationary state after the wad of material hasbeen moved into the main bale chamber 26. Plunger 30 compresses the wadsof crop into flakes to form a bale and, at the same time, graduallyadvances the bale toward outlet 32 of main bale chamber 26. Main balechamber 26 and plunger 30 function as the second stage for cropcompression. When enough flakes have been added and the bale reaches afull (or other predetermined) size, knotters 34 are actuated which wrapand tie twine around the bale while it is still in the main bale chamber26. Needles 36 bring the lower twine up to the knotters 34 and the tyingprocess then takes place. The twine is cut and the formed bale isejected from a discharge chute 38 as a new bale is formed.

Plunger 30 is connected via a crank arm 40 with a gear box 42. Gear box42 is driven by a flywheel 44, which in turn is connected via a driveshaft 46 with the power take-off (PTO) coupler 48. The PTO coupler 48 isdetachably connected with the PTO spline at the rear of the fractionunit, such as a tractor (not shown). PTO coupler 48, drive shaft 46 andflywheel 44 together define a portion of a driveline 50 which is carriedby a chassis 51 and provides rotative power to gearbox 42. Flywheel 44has a sufficient mass to carry plunger 30 through a compression strokeas power is applied to drive shaft 46 by the traction unit. Without theflywheel, a large mechanical load (impulse) is placed on the tractionunit as peak power is required by the baler during operation, such as atthe end of a compression stroke and/or during a stuffer unit stroke.Generally speaking, as balers become increasingly larger the size of theflywheel also becomes increasingly larger. A larger flywheel also inturn typically requires the use of a traction unit with a higherhorsepower rating, to maintain input power to the drive shaft 46 duringoperation, and since higher power is required to start rotation of theflywheel from an at-rest position.

Referring now to FIGS. 1-3, conjunctively, baler 10 also includes anauxiliary power system (APS) 52 which is coupled with the driveline 50in parallel with the flywheel 44, in a mechanical power distributionsense and not necessarily a geometric sense. The APS 52 generallyfunctions to receive power from the driveline 50, store the power, andtransmit the stored power back to the driveline 50.

APS 52 generally includes a power generation device 54 for receivingpower from the driveline 50 and generating power, a power storage device56 coupled with and storing power from the power generation device 54,and a power feedback device 58 for transmitting the stored power back tothe driveline. In the block diagram shown in FIG. 3, the powergeneration device 54 and the power feedback device 58 are configured asthe same unit which can operate with different functionality, such as ahydraulic pump/motor or an electric motor/generator. When configured asa hydraulic pump/motor, the power storage device 56 can be in the formof one or more hydraulic accumulators. Alternatively, when configured asan electric motor/generator, the power storage device 56 can be in theform of one or more ultracapacitors and/or batteries. With this type ofdual functionality, the power storage device 56 is connected with thepower generation device 54/power feedback device 58 in a bidirectionalmanner allowing 2-way flow of power, as indicated by double headed arrow60.

Alternatively, the power generation device 54 and the power feedbackdevice 58 can be separate and discrete units which are each coupled withthe driveline 50 and power storage device 56. For example, the powergeneration device 54 can be in the form of a hydraulic pump, and thepower feedback device 58 can be in the form of a separate hydraulicmotor, each of which are mechanically coupled with the driveline 50 andhydraulically coupled with a power storage device in the form of anaccumulator (not specifically shown). Moreover, the power generationdevice 54 can be in the form of an electric motor, and the powerfeedback device 58 can be in the form of a separate electric generator,each of which are mechanically coupled with the driveline 50 andelectrically coupled with a power storage device 56 in the form of anultracapacitor and/or battery (not specifically shown).

The power storage device 56 shown in FIG. 3 can also be configureddifferently than one or more hydraulic accumulators, ultracapacitorsand/or batteries. For example, the power storage device 56 can beconfigured as an additional mechanical flywheel which receives/transmitspower from/to the driveline 50. The power generation device 54 and thepower feedback device 58 can be configured as a continuously variabletransmission (CVT), and the additional flywheel would somehow be capableof receiving and storing power during off-peak load periods andtransferring the power back to the driveline 50 for use during peak loadperiods.

For purposes of discussion hereinafter, it will be assumed that thepower generation device 54 and the power feedback device 58 are in theform of a singular unit configured as a hydraulic pump/motor. Pump/motor54, 58 is coupled with and under the control of an electrical processingcircuit 62, which can be in the form of an electronic control unit (ECU)or an analog processor. Electrical processing circuit 62 can be adedicated ECU onboard the baler 10, or can also be part of an ECU usedfor other purposes onboard the baler 10. Alternatively, electricalprocessing circuit 62 can also be an ECU onboard the traction unit whichtows the baler 10, and can be coupled with the pump/motor 54, 58 andother components onboard baler 10 in a wired or wireless manner.

Electrical processing circuit 62 controls operation of pump/motor 54, 58in a manner such that power is transmitted to the driveline 50 prior toand during peak load periods on the baler 10, and power is received fromthe driveline 50 during off-peak load periods on the baler 10. Morespecifically, power is transmitted to/from the driveline 50 dependentupon a position of the plunger 30 within the main bale chamber 26,and/or a variable associated with the formation of a slice of cropmaterial within the bale chamber 26. To this end, the electricalprocessing circuit 62 is connected with one or more sensors 64 whichprovide output signals indicative of the position of the plunger 30and/or a crop slice variable. In the embodiment shown in FIG. 3, thesensor 64 is positioned adjacent to flywheel 44 to determine therotational position of the flywheel 44, such as by using a proximitysensor, optical sensor, etc. The position of the flywheel 44 can in turnbe used to establish the position of the plunger 30 within the main balechamber 26. Alternatively, the sensor 64 can be configured to sense avariable associated with crop slice formation within the main balechamber 26. Examples of crop slice formation variables may include amoisture content of the crop material, a thickness of a given slice ofcrop material and/or a positional change of the plunger at maximumcompression for each slice of the crop material. Alternatively, thevariable associated with the crop slice formation can even be input by auser, such as a particular type of crop material being harvested. Otherinput variables may also be used for controlling operation of APS 52.

Referring now to FIG. 4, there is shown a control schematic of the APS52 shown in FIGS. 1-3. APS 52 can be thought of as defining a hydraulicflywheel which is based on an over-center variable displacementpump/motor 54, 58 connected between the accumulator 56 and a tank 66. Inorder to avoid any overpressure, a pressure relief valve 68 is installedbetween the pump/motor 54, 58 and the accumulator 56. A check valve 70is also connected to the tank 66 in order to avoid cavitation of thepump/motor 54, 58. A pressure transducer 72 is used to manage thedisplacement of the pump/motor 54, 58. Basically, during a typical dutycycle, the pump/motor 54, 58 works as a real pump charging theaccumulator 56 when the instant power of the baler 10 is lower than theaverage power (FIG. 5). On the other hand, when the plunger 30 is in acompressing stroke, the pump/motor 54, 58 works as a motor convertinghydraulic power into mechanical power that can be provided to thedriveline 50. In this way, the typical peak power can be avoided and thePTO power provided from the tractor is always close to the averagepower. The pump size is a function of the maximum pressure in theaccumulator 56 and the operating speed of the pump/motor 54, 58. Becauseof the additional gearbox 74 coupled with the driveline 50, the pumpspeed can be increased, e.g., from 1000 RPM (the typical PTO speedduring working conditions) up to approximately 2680 RPM. This higherspeed allows the use of a smaller pump with a higher hydraulicefficiency and faster response time, in contrast with a larger pumpneeded when operating at a lower speed condition.

During operation of the baler 10, the plunger 30 reciprocates back andforth during compression cycles within the main bale chamber 26. In theembodiment of the large square baler shown in the graph of FIG. 5, asthe plunger 30 reciprocates back and forth (indicated by the topgenerally sinusoidal curve 80), the power required at the PTO shaft ofthe large baler can fluctuate between a minimum power requirement up toapproximately four times the minimum power requirement (e.g., betweenapproximately 55 and 215 kW). However, the average power indicated bythe horizontal dashed line 82 is only about two times the minimum powerrequirement (e.g., 107 kW). On the other hand, the power provided by thehydraulic pump/motor 54, 58 to the driveline 50 (indicated by the bottomgenerally sinusoidal curve 84) generally offsets the power fluctuationsrequired at the PTO shaft. Thus, the resultant power required at the PTOshaft is indicated by the generally horizontal line 86 just above theaverage power line 82.

In the embodiment of APS 52 described above, the system is assumed to bea hydraulic system with a pump/motor 54, 58 connected between the PTOcoupler 48 and the flywheel 44. However, the exact location of theconnection between the APS 52 and the driveline 50 can vary. Forexample, referring to FIG. 3, a pump/motor 54′, 58′ (shown in dashedlines as an optional attachment location) can also engage splines orgear teeth (not shown) formed at the periphery of flywheel 44. As afurther example, a pump/motor can be connected with an input shaft 90 ofgearbox 42. Thus, it is apparent that wherever power can be scavengedalong the length of driveline 50, APS 52 can be coupled with thedriveline 50 for transmitting power to/from the driveline 50, in amanner as described above.

While this invention has been described with respect to at least oneembodiment, the present invention can be further modified within thespirit and scope of this disclosure. This application is thereforeintended to cover any variations, uses, or adaptations of the inventionusing its general principles. Further, this application is intended tocover such departures from the present disclosure as come within knownor customary practice in the art to which this invention pertains andwhich fall within the limits of the appended claims.

The invention claimed is:
 1. An agricultural baler, comprising: achassis; a flywheel carried by the chassis; a driveline associated withthe flywheel and couplable with a power take-off (PTO) of a tractionunit; a bale chamber; a plunger reciprocally movable in the bale chamberduring a compression cycle having a compression stroke and a returnstroke; and an auxiliary power system coupled with the driveline, theauxiliary power system configured for receiving power from the drivelineduring a portion of the return stroke of the compression cycle, storingthe power, and transmitting the stored power back to the drivelineduring a portion of the compression stroke.
 2. The agricultural baler ofclaim 1, wherein the auxiliary power system is configured fortransmitting power to the driveline for a portion of the compressionstroke prior to a peak load on the plunger.
 3. The agricultural baler ofclaim 1, wherein the auxiliary power system is configured for receivingpower from the driveline dependent upon: a position of the plungerwithin the bale chamber; or a variable associated with a formation of aslice of crop material within the bale chamber.
 4. The agriculturalbaler of claim 3, wherein the variable associated with the formation ofa slice of crop material within the bale chamber is based on: a type ofcrop material; a moisture content of the crop material; a thickness of agiven slice of the crop material; or a positional change of the plungerat maximum compression for each slice of the crop material.
 5. Theagricultural baler of claim 1, wherein the auxiliary power systemincludes: a power generation device for receiving power from thedriveline and generating power; a power storage device coupled with andstoring power from the power generation device; and a power feedbackdevice for transmitting the stored power back to the driveline.
 6. Theagricultural baler of claim 5, wherein the power storage device is ahydraulic accumulator, and wherein the power generation device includesa hydraulic machine working as a hydraulic pump, and the power feedbackdevice is derived by the hydraulic machine working as a hydraulic motorwhen transmitting the stored power back to the driveline.
 7. Theagricultural baler of claim 6, wherein the hydraulic pump and thehydraulic accumulator are connected via a 2-way fluid connection.
 8. Theagricultural baler of claim 5, wherein the power storage device includesa capacitor or a battery, the power generation device includes anelectric machine working as an electric motor, and the power feedbackdevice is derived by the electric machine working as an electricgenerator when transmitting the stored power back to the driveline. 9.The agricultural baler of claim 8, wherein the electric motor and thepower storage device are connected via a 2-way electrical connection.10. The agricultural baler of claim 5, wherein the power storage deviceincludes a flywheel.
 11. The agricultural baler of claim 1, wherein thedriveline includes a PTO coupler at an input end thereof, and theauxiliary power system is coupled with the driveline between the PTOcoupler and the flywheel.
 12. The agricultural baler of claim 1, furtherincluding a gearbox coupled with the plunger via at least one crank arm,the gearbox including an input shaft connected with the flywheel, thedriveline including the flywheel and the input shaft.
 13. A method ofoperating an agricultural baler, the baler including a chassis, aflywheel carried by the chassis, and a driveline associated with theflywheel and coupled with a power take-off of a traction unit, themethod comprising the steps of: reciprocating a plunger in a balechamber during a compression cycle having a compression stroke and areturn stroke; receiving power from the driveline at an auxiliary powersystem (APS) which is coupled with the driveline, wherein the step ofreceiving power is carried out during a portion of the return stroke ofthe compression cycle; storing the received power in the APS; andtransmitting the stored power back to the driveline during a portion ofthe compression stroke.
 14. The method of claim 13, wherein the step oftransmitting power is carried out during a portion of the compressionstroke prior to a peak load on the plunger.